1. Field of the Invention
The present invention relates to a musical tone control waveform signal generating apparatus which, is synchronized with a start timing when a musical tone is generated, generates a musical tone control waveform signal to be varied over a lapse of time.
2. Prior Art
As disclosed in Japanese Patent Laid-Open Publication No. 61-39097, the conventional apparatus forms a waveform signal which is rapidly raised up from the reference level (e.g., zero level) in synchronism with the start timing of generation of the musical tone, then smoothly attenuated to and maintained at a predetermined level for a while, and thereafter attenuated down. By use of such waveform signals, the conventional apparatus controls an amplitude envelope of the musical tone and another amplitude envelope of the modulation signal by which the musical tone is to be formed.
If the above-mentioned waveform signal is attenuated to and maintained at the predetermined level for a long time, or if the waveform signal is raised up and then maintained at the predetermined level for a long time, the musical parameter to be controlled by the waveform signal should be fixed for a long time, which makes the musical tone to be monotonous.
In addition, the conventional apparatus can merely form a waveform signal which is rapidly raised up from the reference level but cannot form the musical tone signal having various kinds of characteristics.